Branched dextrin production and compositions containing same

ABSTRACT

Branched dextrin and linear oligosaccharides are produced by degrading starch with alpha-amylase followed by fractionating with a gel-type filtering agent. The branched dextrin is useful in the food fabrication.

BACKGROUND AND SUMMARY OF THE INVENTION

The present invention relates to a process for selectively fractionatingbranched dextrin and linear oligosaccharides from a starch-saccharifiedsolution and utilizing the specific properties of the branched dextrinin food products.

Formerly, a process was established for fractionally producing maltoseof a high purity and beta-limit dextrin (branched dextrin), whichcomprises the steps of reacting beta-amylase with liquefied starch,thereby forming a saccharified solution consisting mainly of maltose andbeta-limit dextrin, and then contacting the thus saccharified solutionwith an OH-type anion exchange resin; see Japanese Patent Publication(KOKOKU) No. 46290/1977.

Maltose is a disaccharide formed by the alpha-1,4-linkage of twomolecules of D-glucose and since maltose is lower in sweetness ascompared to sucrose and D-glucose, it is broadly utilized as asweetness-decreasing agent in the field of food fabrication. On theother hand, beta-limit dextrin is a macromolecule having a branchedmolecular structure and is referred to as branched dextrin. Due to itsmolecular structure, beta-limit dextrin is easily soluble into water inspite of being a macromolecule, it has a high viscosity, is stable andis not retrogradated. Accordingly, beta-limit dextrin has attractedattention as a raw material for fabricating food products because itimparts elasticity to food products and is good in preserving moisturein the food products, i.e., is a humectant.

However, there is a recent demand for a material lower in sweetness thanmaltose and concerning branched dextrin, the physical properties of amaterial which has a lower molecular weight than beta-limit dextrin,have been requested by food processors and others.

Starch consists of both linear-structural amylose formed bypolymerization of D-glucose through alpha-1,4-linkages andbranched-structural amylopectin of which the main body is polymerizedthrough alpha-1,4-linkages and the remaining moiety is branched throughthe alpha-1,6-linkage at various places of the main body.

In the case where beta-amylase is reacted with a liquefied solution ofstarch having the structure noted above, since only thelinear-structural amylose and the outer branches of thebranched-structural amylopectin become the target of the attack ofbeta-amylase and the internal structure is not destroyed, maltose andmacromolecular branched dextrin are obtained. See Japanese PatentPublication (KOKOKU) No. 46290/1977. However, in the case wherealpha-amylase is reacted with starch, not only amylose but also thealpha-1,4-linkages of the internal structure of amylopectin are cleavedrandomly and the alpha-1,6-linkages are not attacked. Accordingly, as aresult, a saccharified solution of the linear oligosaccharides which arehigher in degree of polymerization than maltose and branched dextrinwhich is lower in molecular weight than beta-limit dextrin are obtained.

As a result of the present inventors' studies, the inventors havenoticed the above-mentioned facts, from the viewpoint that if a processof selectively fractionating the linear oligosaccharides which arehigher in degree of polymerization than maltose and the branched dextrinwhich is lower in molecular weight than beta-limit dextrin from asaccharified solution of starch (which solution comprises the linearoligosaccharides and the branched dextrin) can be offered in order tosimultaneously satisfy the above-mentioned recent demands in the market,it is possible to answer these recent market demands and, accordingly,the range of application of such linear oligosaccharides and brancheddextrin to food products would be remarkably enlarged.

In Japanese Patent Publication (KOKOKU) No. 46290/1977 noted above,maltose and macromolecular beta-limit dextrin can be separatedeffectively from a saccharified solution of maltose and beta-limitdextrin utilizing the adsorptive property of maltose to an OH-type anionexchange resin. However, a saccharified solution resulting from thedegradation of starch with alpha-amylase containing branched dextrin andlinear oligosaccharides, it has been found that there is no differencebetween the absorptive properties of the linear oligosaccharides andthat of the branched dextrin to an OH-type anion exchange resin. Thismeans that the two substances cannot be effectively separated with anOH-type anion exchange resin.

Thus, it is a problem to fractionate the above-mentioned brancheddextrin and linear oligosaccharides respectively from the saccharifiedsolution containing the two.

As a result of the present inventors' studies fractionating brancheddextrin and linear oligosaccharides from a degradation product of starchby alpha-amylase, the inventors have found that differences are causedbetween the internal invasions to a gel-filtrating agent or between thesliding speeds on the surface, depending upon the difference between thelinear molecular structure of the oligosaccharides and the branchedmolecular structure of the dextrin in the degradation product of starch.Utilizing these differences, the present inventors have succeeded ineffectively fractionating the branched dextrin and linearoligosaccharides respectively from a saccharified solution of thedegradation product of starch.

Accordingly, an object of the present invention is to provide a processfor effectively and selectively fractionating branched dextrin andlinear oligosaccharides from a saccharified solution which has beenobtained by applying alpha-amylase to starch and consists mainly of thebranched dextrin and the linear oligosaccharides, and at the same time,in offering a method for utilizing the thus fractionated products forfood products based on the physical properties of the resultingfractionated products.

The present invention will be explained in detail as follows.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is a schematic illustration of a separation appratus for carryingout the process of this invention.

DETAILED DESCRIPTION OF THE INVENTION

The process of the present invention is characterized in the steps ofcausing alpha-amylase to react with starch, thereby forming asaccharified solution consisting mainly of branched dextrin and linearoligosaccharides, and then contacting the resulting saccharifiedsolution with a gel-type filter agent, thereby selectively fractionatingthe branched dextrin and the linear oligosaccharides in the saccharifiedsolution, respectively.

In the present invention, alpha-amylase is the enzyme reacted with thestarch to form a saccharified solution comprising mainly brancheddextrin and linear oligosaccharides, while the starch is randomlyattacked by the alpha-amylase only at alpha-1,4-linkages of amylose andamylopectin which constitute starch. The resulting saccharified solutioncontains the so-called branched dextrin containing alpha-1,6-linkagesand the linear oligosaccharides containing only alpha-1,4-linkages.

During starch degradation with alpha-amylase, each of the starchcomponents is further reduced in molecular weight and at the limitdegradation with alpha-amylase, the saccharified solution containsbranched dextrin of a polymerization degree of from 5 to 10. which isreferred to as alpha-limit dextrin, linear oligosaccharides mainly of apolymerization degree of from 2 to 6, which contain onlyalpha-1,4-linkages, and glucose.

In the present invention, corresponding to the required physicalproperties of the desired products, a saccharified solution of anappropriate degradation stage is contacted with a gel-type filteringagent, e.g., by flowing down from the top of a column filled with thegel-type filtering agent, for instance, an ion exchange resin, andsubstituting the solution with water in succession. Then, a flowdifference is caused between the flow of the branched dextrin and theflow of the linear oligosaccharides in the saccharified solution, and asa result, the branched dextrin is detected in the first effluentfraction and thereafter, the effluent fraction of the linearoligosaccharides is obtained.

In the present invention, in order to prepare a saccharified solutioncomprising branched dextrin and linear oligosaccharides, thesaccharification of starch with alpha-amylase is carried out first.

Various kinds of starches such as corn starch, potato starch, sweetpotato starch and tapioca starch which are used as the raw material forproducing an ordinary starch sugar as well as alpha-starches thereof andwaxy starch may be used as the starting material.

For saccharifying starch, there is a process in which starch isliquefied by a mechanical liquification method accompanied by heatingand alpha-amylase is reacted with the thus liquefied starch or a processin which alpha-amylase is added to starch slurry and the mixture isdirectly heated to promote degradation of the starch, and in compliancewith the object, the saccharification of starch may be promoted by thecoexistence of beta-amylase.

The extent of starch degradation is generally determined depending uponthe required physical properties of the desired product such asviscosity and the degree of sweetness, and also in consideration of thedegree of ease of the fractionating treatment carried out thereafter.Under these circumstances, a DE in the range of from 10 to 35 issuitable, DE or Dextrose Equivalent being an indication of totalreducing sugars calculated as D-glucose on a dry-weight basis. The DEvalue is inversely related to the degree of polymerization (DP).Unhydrolyzed starch has a DE of virtually zero, whereas the DE ofanhydrous D-glucose is defined as 100.

Although saccharification of starch with alpha-amylase can be carriedout at or below the heat-resisting temperature of alpha-amylase, it ispossible to carry out the saccharification at a lower temperature afterliquefying starch at a high temperature. In consideration of thepossible case where the saccharification is promoted in the coexistenceof beta-amylase, the temperature range of from 45° to 110° C. isvirtually the range of carrying out the process of the presentinvention. As to pH, a pH is chosen from the range of between about 4.5and about 7.0 where the enzyme functions.

Although adjusting the control of starch degradation is carried byadjusting the amount of the enzyme added to the reaction system, theoperating temperature, the operating time period, etc., thesaccharification reaction can be stopped by deactivating the enzyme byheating the system or by adding an acid at the desired end ordegradation point during the reaction.

Although the branched dextrin content of the saccharified solutionobtained as described above depends of the kind and the degradationdegree of the starch, the content is generally in the range of fromabout 25 to 50% of the solid matter in the system and the rest is thelinear oligosaccharides.

It should be understood that pretreatments thought to be useful for thenext step of fractionation are included within the scope of the presentinvention: these pretreatments include usually filtration of the thusobtained saccharified solution for removing the impurities contained inthe raw material, purification by decolorizing the system, andconcentration of the system.

As the gel-type filtering agent used for fractionation of the brancheddextrin and the linear oligosaccharides in the saccharified solutionaccording to the present invention, those usually used materialsprepared from dextran, agar-agar, starch, etc. as base materials and ionexchange resins prepared from polystyrene as base material, etc. may bementioned. Also mixtures of gel-type filtering agents may also be used.Either anion exchange resins or cation exchange resins may be used,however, the cation exchange resins are preferable and particularly thecation exchange resins having a cross-linking degree in the range offrom 4 to 8 are practical. Furthermore, concerning the particle diameterof cation exchange resins, to minimize pressure loss in the operation,it is necessary that the particle diameter is in the range of from 40 to80 mesh and is uniform. Although the cation exchange resins are used astheir salt-type, such as Na salt-type, Ca salt-type or Mg salt-type, theNa salt-type is desirable in general.

When the industrial fractionation of branched dextrin and linearoligosaccharides is carried out according to the present invention, thecontinuous flow of the saccharified solution by a simulated moving bedsystem comprisingy columns, which have been filled with a gel-typefiltering agent and have been connected in multiple stages, ispreferred. From 4 to 6 stages are preferably adopted in the simulatedmoving bed system, and each of the stages is provided with therespective inlets for the original saccharified solution and water andthe respective outlets for the branched dextrins and the linearoligosaccharides. A recycle channel is also provided for carrying thetransfer of the solution through all the stages.

After flowing the saccharified solution through all the stages, theinput and the output of the saccharified solution through each of thestages corresponding to the fractionation pattern is carried out bycontrolling the flow rate, and in the case where the flow rate offlowing-out is distributed through each of the stages in proportion tothe composition ratio of the branched dextrin to the linearoligosaccharides, the saccharified solution can be selectivelyfractionated into the branched dextrin and the linear oligosaccharides.

Although the concentration of the original saccharified solution treatedaccording to the present invention is economically preferably as high aspossible, about 30% to about 50% by weight concentration is practical,in consideration of the pressure loss in the columns. The temperature ofthe original saccharified solution is preferably maintained at about 50°C. to about 70° C. because the pressure loss in the columns relates alsoto the temperature of the solution flowing through the columns andtemperatures of from about 50° C. to about 70° C. prevent fermentatinnof the saccharified solution. As the water for eluting the products,water which is generally used, distilled water or ion-exchanged water ofhigh purity is used preferably at the same temperature as that at whichthe solution is flowed.

The branched dextrin fractionated according to the present invention ispurified and concentrated by an ordinary method or is spray-dried togive the desired product. The linear oligosaccharides are also treatedin the same way as above.

The branched dextrin according to the invention has the followingcharacteristics:

(a) an aqueous 30% by weight branched dextrin solution does notretrodegradate after storing the solution for 30 days at 4° C.,

(b) the mean molecular weight of the branched dextrin is from about 800to about 16,000 (corresponding DE being from about 20 to about 1),preferably from about 1,000 to about 4,000 (corresponding DE being fromabout 16 to about 4), and

(c) the viscosity of the branched dextrin is less than about 500 CP.

The branched dextrin product obtained according to the present inventionhas the following properties:

(1) it does not taste sweet or scarcely tastes sweet,

(2) it dissolves easily in cold water forming a clear solution,

(3) an aqueous solution thereof is not retrogradated even at a lowtemperature without any connection with the concentrations,

(4) it shows a considerably lower viscosity for its DE value than theviscosity of the corresponding ordinary saccharified product,

(5) it makes a clear membrane and the surface of the thus formedmembrane is not sticky,

(6) a powdery product thereof is low in hygroscopicity and retains itspowdery state even under conditions of high humidity,

(7) it is hardly colored even by heating and has good thermal stability,and

(8) it adsorbs a substance having hydrophobic groups in the presence ofwater due to the helix structure of the side chains at the terminal ofits molecule.

Since the branched dextrin possesses these peculiar properties mentionedas above, it exhibits favorable effects by a single property or by thecombination of such properties when utilized in food fabrication. Forinstance, representative applications include the use of properties (1)and (6), enabling the branched dextrin product to be used as aquantity-increasing agent, extender or diluent for powdery foods,medicines, etc. Further, it can be used as powdery base material forproducing powdery soups, powdery spices, etc. by spray-drying whileutilizing the properties (2), (3) and (6). Still further, it can be usedas viscosity-increasing agent for sauces, dressings, ketchups, etc. byvirtue of properties (3) and (4). Furthermore, in the case of mixing thebranched dextrin according to the present invention with surimi of freshfish meat and kneading the mixture, the freezing-denaturation of surimiis prevented and the odor showing a decrease in the freshness of surimiis effectively suppressed by the property (8). In this connections,"surimi" is a wet frozen concentrate of the myofibrillar proteins offish muscle. Moreover, by utilizing the same property, the brancheddextrin according to the present invention improves the whiteness andbrightness of the fabricated aquatic products produced by utilizingsurimi.

Since the branched dextrin according to the present invention can besupplied as may be required for use as an aqueous solution according toproperties (3) and (7) in connection with a particular application, theproduct is easier and more convenient for the users and is alsoeconomical.

The present invention will be explained more concretely while referringto he following non-limitative examples in which all parts andpercentages are by weight unless otherwise indicated.

EXAMPLE 1

The separation device used in this example is shown schematically inFIG. 1. There are 4 columns, each identified with a number. Asaccharified solution and water, both supplied by a quantitative(metering) pump, supply incoming liquids to each column which areadjusted and fed to the distributor located in the top of each column.Collectors are positioned at the base of each column and valves areprovided, one for each column, to the recycle circuit. The recyclecircuit is controlled by a quantitative (metering) pump. Brancheddextrin is collected in one container, the oligosaccharides arecollected in the other.

Corn starch having a moisture content of 13.5% by weight was suspendedin water to prepare an aqueous suspension of 20° Be, and after adjustingthe pH of the aqueous suspension to 6.2, alpha-amylase (made by NOVOIndustry Co., under the trade name of TERMAMIL) was added in an amountof 0.1% by weight of the starch to the aqueous suspension. The thusobtained mixture was subjected to heat treatment for 10 minutes at 105°C. After cooling the thus obtained liquefied starch solution to 65° C.,an additional 0.1% by weight of alpha-amylase was added and the mixturewas retained at the same temperature for 4 hours to promotesaccharification.

The DE value after stopping the reaction by adjusting the pH to 4 usingaqueous HCl was 22.7. Then, the thus obtained saccharified solution wassubjected to usual decoloration and purification with activated carbonand an ion exchange resin (1:2 ratio by volume mixture of Amberlite IR120 and Amberlite IRA 411), and the thus decolorized and purifiedsolution was concentrated to a concentration of 40% by weight.

The saccharide composition of the thus obtained saccharified solutionconsisted of 2% by weight of glucose, 5% by weight of maltose, 15% byweight of maltotriose, 6% by weight of maltotetraose, 12% by weight ofmaltopentaose, 20% by weight of maltohexaose and 40% by weight ofbranched dextrin.

Into each column of an apparatus of the simulated moving bed apparatusas shown in the attached FIGURE, which consisted of four columns eachwith a capacity of 1 liter having a diameter to height ratio of 1:2.each filled with a gel-type polystyrene based, divinylbenzene (DVB)cross-linked, strongly acidic cation exchange resin. The cross-linkingdegree of the ion exchange resin was 4 and the particle diameter was 60mesh. The ion exchange resin was used as the Na salt type.

On the upper surface of the internal portion of the columns,distributors were provided and connected respectively to the inlet tothe columns for the original saccharified solution and water which hadbeen delivered from quantitative pumps, and the respective outlets fromthe columns for the fractionated solutions of the branched dextrin andthe linear oligosaccharides were connected to the respective collectorsprovided on the bottom surface of the internal part of the columns. Onthe outlet and the inlet of each of the columns, electromagnetic valveswere provided to control the opening and closing of the valves by atimer, and a recycle channel was provided for transferring the solutionthrough all the stages via a quantitative pump.

The conditions of flowing the solution in the operation of fractionationwhile using the above-mentioned apparatus were as follows.

The 4 columns were numbered in the direction of the flow of the solutionas 1 through 4.

In the first place, 100 ml of the original saccharified solution of aconcentration of 40% by weight were passed through column 1 over exactly10 minutes and 150 ml of water were passed through column 3 over exactly10 minutes. During that time period, the discharge of the saccharifiedsolution was carried out from the respective columns 2 and 4 whilecontrolling the flow ratio according to the composition ratio of theoriginal saccharified solution, namely the composition ratio (40:60) ofthe branched dextrin to the linear oligosaccharides. The solution of thebranched dextrin was discharged from column 2, and the solution of thelinear oligosaccharides was discharged from column 4.

Next, 630 ml (void volume of each column) of the transfer solution wascarried out through the recycle channel exactly over 30 minutes andafter promoting the fractionation pattern within each column by onestep, the out-flow and in-flow of the solution were operated at theposition of each column advanced by one step in the same manner asabove. The above-mentioned operations were continuously repeated.

During continuous operations, the temperature of the flowing solutionand the temperature of water used in the operations were maintained at60° C. A portion of each of the fractionally collected solutions wasrespectively purified and then concentrated to be syrup and theremaining part was subjected to spray-drying.

As a result of analysis of the respective specimens, the saccharidecomposition of the fractionated branched dextrin consisted of 90% byweight of branched dextrin, 3% by weight of maltohexaose, 2% by weightof maltopentaose, 1% by weight of maltotetraose, 2% by weight ofmaltotriose and 2% by weight of maltose. The DE value of the brancheddextrin was 8, corresponding to the mean molecular weight of about2,000.

The saccharide composition of the linear oligosaccharides consisted of3% by weight of glucose, 7% by weight of maltose, 25% by weight ofmaltotriose, 10% by weight of maltotetraose, 20% by weight ofmaltopentaose, 33% by weight of maltohexaose and 2% by weight ofbranched dextrin.

EXAMPLE 2

To the saccharified solution of starch obtained in the same manner as inexample 1, additional alpha-amylase was added in an amount of 1% byweight based on the starch, and the mixture was subjected to furthersaccharification for 10 hours at 65° C.

The DE value after carrying out the saccharification showed 34.5 and thesaccharide composition of the saccharified solution consisted of 7% byweight of glucose, 12% by weight of maltose, 21% by weight ofmaltotriose, 8% by weight of maltotetraose, 27% by weight ofmaltopentaose and 25% by weight of branched dextrin.

Next, the fractionation of the saccharified solution was carried out inthe same manner as in example 1. Since the content of the brancheddextrin in the original saccharified solution was 25% by weight, exceptfor controlling the discharge ratio 25:75 of the saccharified solutionaccording to the composition ratio (25:75) of the saccharified solution,the same operations as in example 1 were carried out.

The respectively collected fractionated solutions were purified andconcentrated to be syrups, and the branched dextrin syrup wasspray-dried.

As a result of analysis of the respective specimens, the saccharidecomposition of the fractionated branched dextrin consisted of 85% byweight of branched dextrin, 10% by weight of maltopentaose, 3% by weightof maltotriose and 2% by weight of maltose. The DE value of the brancheddextrin was 16, corresponding to the mean molecular weight of about1,000.

On the other hand, the saccharide composition of the linearoligosaccharides consisted of 9% by weight of glucose, 15% by weight ofmaltose, 27% by weight of maltotriose, 11% by weight of maltotetraose,33% by weight of maltopentaose and 5% by weight of branched dextrin.

EXAMPLE 3 Preparation of a Powdery Soup

Thirty percent (by weight based on the solid matter of a soy sauce) ofbranched dextrin (DE=12) was added to the soy sauce as a dryingadjuvant, and the thus prepared mixture was powdered with a spray-drierat a hot wind temperature of 150° C. after sterilizing the mixture in aplate-type sterilizer.

The moisture content of the thus obtained product was 4% by weight.

Two recipes for powdery soups produced by utilizing the powdered soysauce are as follows:

Onion Consomme Soup

14.5% by weight of sodium chloride

3.0% by weight of MSG

8.5% by weight of onion essence powder

10.0% by weight of the powdery soy sauce

15.0% by weight of meat essence powder

15.0% by weight of beef essence powder

5.0% by weight of granulated sucrose

0.2% by weight of white pepper

0.1% by weight of celery powder

0.1% by weight of malic acid

3.5% by weight of carrot essence powder, and

25.0% by weight of branched dextrin.

Chicken Cream Soup

6.2% by weight of sodium chloride

2.0% by weight of granulated sucrose

1.0% by weight of MSG

6.0% by weight of the powdery soy sauce

18.0% by weight of powdered cream

10.0% by weight of defatted powdered milk

5.0% by weight of onion essence powder

0.2% by weight of white pepper

0.03% by weight of celery powder

2.0 % by weight of FD chicken powder

1.0% by weight of chicken essence powder

1.2% by weight of locust bean gum

16.0% by weight of potato starch

30.4% by weight of branched dextrin

0.15% by weight of AD parsley, and

0.8% by weight of xanthane gum.

Since powdered soy sauce is hygroscopic, it is desirable to carry outthe preparation of powdery foods using the powdered soy sauce in anair-conditioned room with a relative humidity of not higher than 50%. Inpreparing onion consomme soup, 150 ml of hot water is poured to 6 g ofthe powdery soup mentioned above. In preparing chicken cream soup, 150ml of hot water is poured to 13 g of the powdery soup mentioned above.

EXAMPLE 4 Preparation of a Powdery Spice

1 kg of peppermint oil, 1 kg of synthetic menthol and 1 kg of thebranched dextrin obtained in example 1 were mixed with 5 liters of waterto prepare an emulsion, and the thus obtained emulsion was spray-driedat a drying temperature of from 110° to 120° C. to obtain the product.

EXAMPLE 5

Saccharides, polyphosphoric acid sodium salt and a surfactant were mixedand kneaded according to the following recipe.

    ______________________________________                                        Recipe                                                                        No. of Recipe    1         2      3                                           ______________________________________                                        Sucrose (wt %)   3         0      3                                           Sorbitol (wt %)  3         3      0                                           Branched dextrin (wt %)                                                                        0         3      3                                           (DE = 8)                                                                      PP Na (wt %)       0.3       0.3    0.3                                       Surfactant available                                                                           0           0.2  0                                           on the market (wt %)                                                          ______________________________________                                    

Pollack surimi was mixed with each additive according to the recipes andcomparative tests were carried out.

After preserving the surimi added with each of recipes at -20° C., theHW (hunter whiteness), and the L (lightness) of the surimi weremeasured.

The results are as follows:

    ______________________________________                                        Just After Refrigeration of Surimi                                            No. of      Moisture            HW   L                                        specimens   content (%)                                                                              pH       (%)  (%)                                      ______________________________________                                        1     (Control) 79.9       7.49   20.1 48.8                                   2               79.6       7.49   25.5 55.2                                   3               80.3       7.46   22.8 51.9                                   ______________________________________                                    

Pollack surimi mixed with each additive according to the recipes wasfurther mixed with sugar, starch, MSG, etc. and kneaded, and then themixture was heated at 90° C. for 30 minutes to give kamaboko. The HW,the L and JS (jelly strength) of the kamaboko were measured.

The results are as follows:

    ______________________________________                                        Physical Properties of the Kamaboko                                           No. of   Moisture           HW    L    JS                                     specimens                                                                              content (%)                                                                              pH      (%)   (%)  (g × cm)                         ______________________________________                                        1   (control)                                                                              74.9       7.14  42.0  69.3 491                                  2            74.9       7.22  44.5  71.4 491                                  3            74.9       7.24  43.2  70.5 483                                  ______________________________________                                    

As are seen in the above test results, branched dextrin added to thefood products (surimi and kamaboko) prevented the freeze-deteriorationof the food products and at the same time improved the whiteness and thelightness of the food products.

Although the raw surimi subjected to these tests showed some decrease infreshness and gave out a stench, branched dextrin added to such a rawsurimi clearly suppressed the stench while exhibiting a deodorizingeffect.

What is claimed is:
 1. A process for producing branched dextrin whichprocess comprises the steps of:(a) reacting alpha-amylase with starch toproduce a saccharified solution composed mainly of branched dextrincontaining alpha-1,6-linkages and linear oligosaccharides containingalpha-1,4-linkages, and (b) contacting the thus obtained saccharifiedsolution with a gel-type filtering agent thereby selectivelyfractionating and separating said branched dextrin substantially free ofsaid linear oligosaccharices, said branched dextrin having a meanmolecular weight of from about 800 to about 16,000.
 2. A processaccording to claim 1, wherein the degree of enzymatic degradation ofstarch due to alpha-amylase is in the DE range of from 10 to
 35. 3. Aprocess according to claim 1, wherein said gel-type filtering agent isan ion exchange resin having a cross-linking degree of from 4 to
 8. 4. Aprocess according to claim 1, wherein the selective fractionation ofsaid branched dextrin and said linear oligosaccharides is carried out bya simulated moving bed system.
 5. Branched dextrin, substantially freeof linear oligosaccharide having a mean molecular weight of from about800 to about 16,000 with a corresponding DE from about 20 to about 1produced by the process of claim
 1. 6. A solution of branched dextrin,substantially free of linear oligosaccharide, having a mean molecularweight of from about 800 to about 16,000 with a corresponding DE fromabout 20 to about 1 produced by the process of claim 1.